Some Milestones in History of Science About 10,000 bce, wolves

Marconi, the following year, to make a successful attempt to send radio signals across the Atlantic
ocean.
 
In 1901, Ricci-Curbastro and Tullio Levi-Civita, in Méthodes de calcul différentiel absolu et leurs 

applications, developed a coordinate-free tensor calculus using Christoffel's symbols. 
 
In 1901, Willis H. Carrier invented the industrial air conditioner.  
In 1902, W. Bateson, in Mendel's Principles of Heredity: A Defense, in which he demonstrated that 
Mendel's principles apply also to animals.  In the same year, he coined 'allomorph,' and, before 1909,
also 'genetics,' 'homozygote,' 'heterozygote,' and 'epistatic.'
By 1902, Karl Landsteiner found that human blood was one of four types, A, B, A-B, and O, thus 
making transfusions safe.
In 1902, E. Overton supported Bernstein's idea with evidence that exogamous sodium ions were
responsible for the impulse (Overton 1902). 
In 1902, Fischer proposed that proteins consist of chains of amino acids.
In 1902, Ivan Pavlov combined associative learning with reflex acts, postulating the existence of
associated stimuli, or 'conditioned responses.' 
 Later, he also described two non-associated 
behavioral modifications, 'habituation' and 'sensitization.' 
In 1902, Lucien Claude Cuénot proposed that a gene plus two enzymes controlled hair color in mice;
if both enzymes were present, it was grey, or if only one, it was black. 
In 1902, J. W. Gibbs, in Elementary Principles in Statistical Mechanics Developed With Special
Reference to the Rational Foundation of Thermodynamics, offered a more general approach to 
statistical mechanics than Boltzmann or Maxwell.  What Boltzmann had called the Ergoden, Gibbs 
called the 'grand canonical ensemble,' and the process of achieving it is known as 'ensemble 
averaging.'  The principle theme is the "analogy...between the average behavior of a canonical
ensemble of systems and the behavior of a physical system obeying the laws of thermodynamics"
(Klein 1976:392).  This ensemble, or function, has a simple physical interpretation: the probability of 
finding at a certain time t a point in the small region of phase space around the point q at momentum 
p.  That Gibbs' and Boltzmann's books did not become obsolete is due to the adequacy of classical
theory in dealing with the relations between molecules, whereas quantum theory is necessary to deal
with a molecule's internal structure.   
 
In 1902, Poincaré, in La science et l'hypotheése, noted that it doesn't matter whether or not aether 
exists, that 'what is essential for us is that everything happens as if it existed....  [It] is only a 
convenient hypothsis, [and] some day, no doubt, the aether will be thrown aside as useless" (Poincaré
1902:211-212). 
 
In 1902, Bertrand Arthur William Russell found the 'ultimate paradox:' If the set of all sets which do
not contain themselves nonetheless contains itself, then it cannot belong to the set of all sets which
do not contain themselves.  If it does not contain itself, then it must belong to the set of all sets which 
do not contain themselves.
 
In 1903, the beginning of cytogenetics occurred when, in independent accounts, Bovari and Walter 
Stanborough  Sutton pointed out that chromosomes permutated themselves in cell division, halved
their complement in germ cell formation, and paired again in fertilization, in a "physical dance that kept
perfect step with Mendel's abstract algebra" (Judson 1979:206). 
In 1903, Willem Einthoven invented a string galvanometer which enabled him to produce the first
electrocardiogram, or graphic record of the action of the heart. 
In 1903, Richard Kraus distinquished natural, or normal, antibodies from acquired immune antibodies
according to their 'avidity,' or strength.  Both Ehrlich  and  Landsteiner, in contrast, were intent on 
reducing the difference to one of quantity. 
In 1903, Metchnikoff, in Études sur la nature humaine, translated as The Rhythm of Life, argued that 
death from old age was only to be feared because of the accompanying pain and that, as science
advanced and old age became less onerous, a natural wish to die would manifest itself.
 
In 1903, Tsvet made the principle of adsorption the basis of a new method which would permit the
extraction from a solution of pigments in unchanged forms (Tsvet 1903), and subsequently developed 
and named it 'chromatography' (Tsvet 1906).
In 1903, Orville Wright and Wilbur Wright achieved flight in a manned, gasoline power-driven, 
heavier-than-air flying machine. 
 
["The emergence of genetics coincided with the redefinition of the term heredity to refer exclusively to 
transmission: what had previously been seen as two aspects of a single subject (transmission and
development) came to be regarded as distinct concerns.  By the early decades of the twentieth 
century, the study of transmission had become the province of genetics, whereas that of
development--now split off from genetics--continued as the province of embryology" (Keller 1995:4-
5).  At the same time as thinking about evolution turned from Haeckelian comparative anatomy and 
Weismannian speculation to the laboratory, embryologists shifted Haeckelian phylogenetic
recapitulation and Weismannian concentration on heredity to a concern for experiment and
developmental mechanics, specifically to His's immediate causes of morphologies and Roux's 

Entwicklungsmechnik, or developmental mechanics.  Unlike many cytologists, and later geneticists, 
who centered their investigations on the chromosomes, embryologists centered theirs on the
cytoplasm of the egg.  The geneticists were essentially reductionist; the embryologists integrative or
holistic.  Genetic methods looked for differences through interbreeding; embryological methods, for
commonality.]
 
In 1904, Nuttall, using precipitin tests of blood serum proteins, inferred the close phylogenetic 
relationship between humans and apes. 
In 1904, T. R. Elliott recognized that chemical agents, and specifically adrenaline, acted as
neurotransmitters in peripheral nerves, helping the nerve signal across the synapse (Elliott 1904). 
In 1904 and 1905, Arthur Harden discovered that the presence of phosphate was essential to the
enzymes which ferment sugar.
 
In 1904, Lorentz, in "Electromagnetic Phenomena in a System Moving with Any Velocity Less than
that of Light," formulated the so-called 'Lorentz transformation,' which describes the increase in mass,
the shortening of length, and the time dilation of a body moving at speeds close to that of light, by
which the space-time coordinates of a moving system can be correlated with those of any other 
system. "The quality of not changing under this or some other transformation is called invarience
[which] is the mathematical expression of symmetry....  Both Maxwell's electrodynamics and [Albert] 
Einstein's special relativity are descriptions which are invariant under Lorentz transformation" (Park 
1990:355-356).  
 
In 1904, Hantaro Nagaoka proposed a 'Saturn model' of the atom with a nucleus and many electrons
in a ring around it.
 
In 1904 or earlier, Poincaré gave the name the 'principle of relativity' to the proposition that, since the 
Universe contained no standard of absolute rest, anything is moving only in respect to something
else.  
 
In 1904, Ramsey discovered radon.
 
In 1904, L. P. Teisserenc de Bort published the results of 581 free balloon ascents in which 
instruments measured the temperatures and pressures in the atmosphere to a height of about 14 km.
In 1905, Metchnikoff introduced the theory that white blood cells are able to engulf and kill bacteria
(Metchnikoff 1905). 
 
In 1905, Nuttall demonstrated the importance of bacteria for digestion.
In 1905, John Newport Langley discovered acetycholine, but it was not recognized in the brain until
F. McIntosh did so in 1941 (Langley 1905). 
In 1905, F. Knoop deduced the beta-oxidation of fatty acids. 
In 1905, Edmund Beecher Wilson, author of Cell Biology in Development and Heredity (published in 
1896 and numerous later editions and others), discovered that the X chromosome is linked to the sex
of the bearer. 
 
In 1905, Freud, in Drei Abhandlungen zur Sexualtheorie, redrew the line between normality and 
mental illness: "Not some mysterious hereditary degeneration read back into infancy, but an otherwise
normal childhood experience that would bear a resemblance to the adult behavior (or in the case of 
neurosis, to adult repressed fantasy)" (Kerr 1993:93).  In the same year, in a postscript to another 
paper, Freud argued that patients sought to reexperience old erotic situations by transferring them to
their physician.
 
In 1905, Arrhenius expressed concern about global warming as a result of burning fossil fuels.
 
In 1905, in the first of three articles in a single issue of Annalen der Physik, "Übereien die Erzeugung 
und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt," Einstein  sought an 
explanation of the photoelectric effect, the anomaly that electrons are emitted from the surface of a
metal only if the incident light is sufficiently short wave length.  Einstein determined that a massless 
quanta of light, which he called a 'photon,' in order to break the attractive forces holding the electrons
in the metal, would have to impart the required energy according to Planck's radiation law.  "This 
elegantly quantified reversion to Newton's corpuscular theory of light by Einstein was one of the 
milestones in the the development of quatum mechanics" (Dictionary of Physics 2000:387-3880.
In 1905, in the second article, "Über die von der molekularkinetischen Theorie der Wärme geforderte
Bewegung von in rubenden Flüssigkeiten suspendierten Teilchen," Einstein  studied some 
consequences of assuming that liguids and gases are composed of atoms.  Even though too small to 
see, he conjectured that the presence of atoms could be confirmed if objects large enough to see
were influenced by their fluctuations.  This he demonstrated by showing that "a particle suspended in
a liquid and observed with a microscope would be seen to dance around under the influence of the
random fluctuations in pressure that are to be expected if the liquid consists of atoms in rapid motion"
(Park 1990:309).  This phenomena was well known to microscope users as Brownian movement.  By 
inverting  Boltzmann's formula, Einstein described its mathematics, deriving the probability of a

macroscopic state for the distribution of gas molecules, in terms of the entropy associated with that
state.  
 
In 1905, in the third article, "Zur Electrodynamik bewegter Körper" ("On the Electrodynamics of
Moving Bodies"), Einstein evolved the Special Theory of relativity by working out the consequences
of two postulates: One, the laws of nature are the same for all frames of reference in uniform, i.e., not 
accelerating, relative motion, and, two, light is propagated at a constant velocity which, unlike things in
ordinary experience, is independent of the movement of the emitting body and the observer.  In other 
words, observers in motion with respect to one another will disagree about length and time in the
other's system.  This theory "led to the discovery that time is associated as a fourth coordinate on an 
equal footing with the other three coordinates of space, and that the scene of material events, the 
world, is therefore a four-dimensional,  metrical continuum" (Weyl 1918a:201).  The Special Theory 
was invented as "a way--the only way--to assure the complete validity and self-consistency of 
Maxwell's equations" (Wheeler and Ford 1998:166).  It also resulted in mathematical equations which 
confirmed the 'Lorentz transformation' and contained the velocity of a moving body at the velocity of
light relative to an observer, V=(v
1
+v
2
)/(1+v
1
v
2
/c
2
)(Einstein 1905a:37-65). "The real (and great) merit 
of the Special Theory...was pedagogical.  It arranged the old confusing material in a clear deductive
pattern" (Everitt 1976:215).  
 
Later in 1905, in a second paper of the Special Theory of relativity, "Ist die Trägheit einer Körpers von
seinem Energiehalt abhängig?" ("Does the Inertia of a Body Depend upon Its Energy Content?"),
Einstein wrote that "if a body gives off the energy L in the form of radiation, its mass diminishes by 
L/c
2
....  The mass of a body is a measure of its energy content" (Einstein, quoted in Kantha 1996:46). 
This was published in Annalen der Physik in 1906 and put an end to speculation that the Sun's energy
came from radiation (Einstein 1905b:69-71).
In 1905, Poincaré, in "Sur la dynamique de l'electron," obtained, independently of Einstein, many of 
the results of the Special Theory of relativity.  However, he postulated nonelectric forces, or 'stresses,'
to give stability to an electron; these were rendered irrelevant by quantum theory.
 
In 1905 and 1907, Ejnar Hertzsprung published papers relating colors and brightnesses of stars in a 
systematic way, and recognizing dwarf and giant stars.
In 1906, W. Bateson and Reginald Crundall Punnett reported less-than-independent assortment, or 
'linkage,' in gene alleles on the same chromosome in sweet peas. 
In 1906, Sherrington showed, in his book The Integrative Action of the Nervous System, that those 
cells which send their fibers and impulses directly to the limb muscles can be influenced to fire by
excitation or not to fire by inhibition. 
 
In 1906, Frederick Gowland Hopkins noticed that 'accessory food factors,' later called vitamins, were 
essential to the growth of rats. 
 
In 1906, Andrei Andreyevich Markov described sequences of randomly linked probability variables in
which the future variable is determined by the present variable, but is independent of the way in which
the present variable arose from its predecessors. These 'Markov chains' launched the theory of 
stochastic processes. 
 
In 1906, Walther Hermann Nernst stated a new tenet, often called the Third Law of Thermodynamics,
according to which if a chemical change takes place between substances that are at absolute zero 
there is no change in entropy.
 
 
Beginning in 1906, Ferdinand de Saussure lectured on the structural principles of general linguistics,
including the reciprocity of phonemes and the opposition of diachrony and synchrony (Saussure
1915). 
 
In 1907, Ross Granville Harrison cultivated amphibian spinal cord, demonstrating that axons are 
extensions of single nerve cells.  In so doing, he invented tissue culture (Harrison 1907). 
 
In 1907, Alois Alzheimer characterized the senile degeneration , to which he loaned his name, by the
'senile plaques' and 'neurofibrillary tangles' which he found in an autopsied brain.
 
In 1907, Arrhenius published Immunochemistry: The Application of the Principles of Physical
Chemistry to the Study of Biological Antibodies, thereby coining the term 'immunochemistry.' 
 
In 1907, Arrhenius hypothesized that life on earth is descended from interstellar microorganisms,
sucked in by gravity and pushed out by radiation.  This hypothesis is usually called 'panspermia,' 
meaning 'life everywhere.'  Since, at that time, it was assumed that, even though stars were born and 
died, the Universe was in essence eternal and unchanging, the question of its origin did not have to
be addressed (Gribbin and Gribbin 2000:3-4).
In 1907, Einstein, in "Über die vom Relativitätsprinzip geforderte Trägheit der Energie," deduced the 
expression for the equivalence of mass and energy, K
o
=mV
2
, where K
o 
is energy, m is mass, and V
2
 is 
the speed of light squared.  ["E=mc
2
" was the title of a Science Illustrated article which Einstein wrote 
in 1954 (Kantha 1996:46).]  This relation says that "a sufficiently energetic packet of radiation (a

photon) can convert into matter with the appropriate mass, and vice-versa" (Gribbin 1998a:172).
In 1907, Luitzen Egbertus Jan Brouwer completed his doctoral dissertation on the logical foundations 
of mathematics which marked the beginning of the Intuitionist School. 
In 1908, Archibald Edward Garrod, in Inborn Errors of Metabolism, recognized that gene products are 
proteins and showed that certain rare, inherited disorders were caused by the absence of specific 
enzymes.  W. Bateson, in 1902, had suggested to him the probability that an inherited disorder was
due to a recessive gene. 
In 1908, Godfrey Harold Hardy worked out the equilibrium formula for a population heterogenous for
a single pair of alleles: Assuming the truth of Mendel's laws (and generalizing them), the resulting 
combinations will expand into the binomial distribution, or p
2
(AA) + 2pq(Aa) + q
2
(aa), where p is the 
initial frequency of the dominant A in a population and q the initial frequency of the recessive a.  This 
formula was derived independently by Wilhelm Weinberg, and is thus known as the Hardy-Weinberg 
equilibrium formula.  It provided the first baseline for assessing the effects of mutation. 
 
In 1908, William McDougall, in An Introduction to Social Psychology, postulated that human beings 
have as many as a dozen different basic instincts, e.g., curiosity, pugnacity, self-abasement, etc. 
In 1908, Robert Andrews Millikan determined the probable minimum unit of an electrical charge, that
is, of an electron. Later, he named 'cosmic rays.'  
In 1908, Planck, attacking Mach's position that physical theories were based solely on sense data,
held that "the physicist creates the system of the physical world by imposing form upon it..., creat[ing] 
the mathematical structures which organize empirical facts" (Janik and Toulmin 1973:138). 
 
In 1908, Hermann Minkowski took Einstein's algebraic expression of the Special Theory of relativity
and geometrized it, coupling space and time into a four-dimensional continuum, and providing a 
framework for all later mathematical work in relativity.  "Henceforth, space by itself, and time by itself, 
are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an
independent reality" (Minkowski 1908:75).
In 1908, Frank W. Very suggested that the "atmospheres of the major planets would allow optically
visible sunlight to pass through to the ground, which would heat up and reradiate at infrared
wavelengths.  Because the atmospheres are opaque to the infrared spectrum, this radiation would be 
trapped beneath the atmosphere where it could heat up the planetary surface" (Lang and Gingerich
1979:153).
 
In 1908, Henrietta Swan Leavitt, after years of analyzing the two Magellanic Clouds, reported finding
1,777 variable stars, and, having derived the periods of a few 'Delta Cepheid-type' variables, also 
reported that the brighter among them tended to have longer pulsation cycles.
In 1908, George Ellery Hale completed building the 60-inch reflecting telescope on Mount Wilson in 
California.
 
In 1908, Zermelo founded axiomatic set theory.
In 1909, Charles D. Walcott discovered the Cambrian Burgess Shale fossils. 
In 1909, Andrija Mohorovicic observed a discontinuity within the Earth that marks the junction
between the crust and the mantle.
 
In 1909, reports by Correns and Erwin Baur described the non-Mendelian inheritance of a factor 
influencing chloroplast development, thus beginning the recognition of extra-nuclear or cytoplasmic 
genetics. 
 
In 1909, F. Meves proposed that mitochondria originate from preexisting structures of the same kind
and carry their own heredity. 
 
In 1909, Wilhelm Johannsen published Elemente der exakten Erblichkeitslehre which was concerned 
with how to grow pure lines of beans in view of the fact that natural selection can influence change
only if there is genetic variability.  To this end he distinquished between 'genotype' and 'phenotype,'
the one being variant due to heredity and the other being due to environment.  Naming Mendel's 
algebraic units 'genes,' Johannsen understood that to mean that each gene underlies a single trait.
In 1909, W. Bateson, in a much expanded new edition of Mendel's Principles of Heredity, echoed 
Mivart's idea that what was selected was born fit.  Bateson believed that the variation giving rise to 
new species was saltational, but present from the beginning of life and waiting for disinhibition and
expression.  He coined the term 'genetics,' but abjured theorizing: Heredity, the Mendelian variations
which he encountered in experiments, failed to explain big changes.  By contrast, Pearson assumed 
that selection brought about stable varieties or species based on the small, incremental differences or 
gene frequencies in individuals belonging to groups of vast size.
In 1909, Kørbinian Brodmann , in Vergleichende Lokaisationslehre der Groshirnrinde, published a 
map of the cortex with 52 areas, each with a function.  This map is still in use.
In 1909, Edward Tyson Reichert conceived the ambition to plot the evolutionary relationships among
species by the divergences between their hemoglobin molecules.  To this end he published six 

hundred micrographs of hemoglobin crystals.
In 1909, Charles Jules Henri Nicolle showed that typhoid fever is transmitted by body lice.
 
In 1909, Fritz Haber, in order to synthesize ammonia from its elements, developed the first
commercially important high-pressure chemical process.
In 1909, Hans Geiger and E. Marsden, under Rutherford's direction, scattered alpha particles with 
thin films of heavy metals, providing evidence that atoms possessed a discrete nucleus.
 
In 1909, Vito Volterra, in "Sulle equazioni integro-differenziali della teoria dell'elasticità," writing on the 
hereditary phenomena, said that the delayed effects tend to zero when time tends to infinity.  
 
In 1909, Karl Bohlin suggested that the center of the Milky Way lies within the large collection of
globular clusters in the direction of Sagittarius.
In 1909, Vesto M. Slipher showed "photographic emulsions could record the infrared spectrum
and...found that the major planets exhibited infrared absorption lines not present in sunlight. 
Subsequently, these bands were identified with amonia and methane" (Lang and Gingerich 1979:67).
In about 1909, David Hilbert's work on integral equations established the basis for his subsequent
work on infinite-dimensional space, which came to be called 'Hilbert space.'
In 1910, Francis Peyton Rous induced a tumor using a filtered extract of chicken tumor cells.
 
In 1910, Konstantin S. Mereschovsky published an essentially modern view of the bacterial origin of
what later came to be called eukaryotic cells.
In 1910, Thomas Hunt Morgan discovered the white-eye sex linkage in Drosophila, relating it to